Listed below are the diagnostic criteria for the five Pervasive Developmental
Disorders (PDDs), also known as Autism Spectrum Disorders (ASDs), as defined
by the Diagnostic and Statistical Manual of Mental Disorders - Fourth Edition
(DSM-IV), published by the American Psychiatric Association, Washington D.C.,
1994, the main diagnostic reference of mental health professionals in the U.S.

B. Delays or abnormal functioning in at least one of the following areas, with
onset prior to age 3 years: (1) social interaction, (2) language as used in
social communication, or (3) symbolic or imaginative play.

C. The disturbance is not better accounted for by Rett's disorder or childhood
disintegrative disorder.

This category should be used when there is a severe and pervasive impairment
in the development of reciprocal social interaction or verbal and nonverbal
communication skills, or when stereotyped behavior, interests, and activities
are present, but the criteria are not met for a specific pervasive developmental
disorder, schizophrenia, schizotypal personality disorder, or avoidant personality
disorder. For example, this category includes "atypical autism" --presentations
that do not meet the criteria for autistic disorder because of late age of
onset, atypical symptomatology, or subthreshold symptomatology, or all of these.

C. The disturbance causes clinically significant impairment in social, occupational,
or other important areas of functioning.

D. There is no clinically significant general delay in language (e.g., single
words used by age 2 years, communicative phrases used by age 3 years).

E. There is no clinically significant delay in cognitive development or in
the development of age-appropriate self-help skills, adaptive behavior (other
than in social interaction), and curiosity about the environment in childhood.

F. Criteria are not met for another specific pervasive developmental disorder
or schizophrenia.

A. Apparently normal development for at least the first 2 years after birth
as manifested by the presence of age-appropriate verbal and nonverbal communication,
social relationships, play, and adaptive behavior.

B. Clinically significant loss of previously acquired skills (before age 10
years) in at least two of the following areas:

(1) expressive or receptive language

(2) social skills or adaptive behavior

(3) bowel or bladder control

(4) play

(5) motor skills

C. Abnormalities of functioning in at least two of the following areas:

(1) qualitative impairment in social interaction (e.g., impairment in nonverbal
behaviors, failure to develop peer relationships, lack of social or emotional
reciprocity)

(2) qualitative impairments in communication (e.g., delay or lack of spoken
language, inability to initiate or sustain a conversation, stereotyped and
repetitive use of language, lack of varied make-believe play)

(3) restricted, repetitive, and stereotyped patterns of behavior, interests,
and activities, including motor stereotypies and mannerisms

DD. The disturbance is not better accounted for by another specific pervasive
developmental disorder or by schizophrenia.